“…To address the concerns from differential selection into smoking, studies investigating the effect of smoking on earnings have often invoked strong econometric assumptions. Many of these studies have used distinct approaches such as covariance restrictions (Auld, 2005), instrumental variables (Anger and Kvasnicka , 2010;Van Ours, 2004), longitudinal records (Grafova and Stafford, 2009;Levine et al, 1997), and more recently twin siblings (Lång and Nystedt, 2018) to overcome issues of selection. On the whole, these studies estimate the total effect of smoking on earnings, and they find that smoking reduces earnings between 8% and 24%.…”